Live-wire detector



\ July 19, 1932.. WALTER 1,867,901

LIVE WIRE DETECTOR Filed NOV. 12, 1928 INVENITOR Mug/g ATTORNEYS atented July 19, 1932 STATES team PATEN GEGEQE FRED WALTER, F MAPLEWOOD, NEW JERSEY, ASSIGNOR OF ONE-HALF TO HARVEY P. SLEEPER, OF SHQRT HILLS, NEW JERSEY LIVE-WIRE DETECTOR Application filed November 12, 1928. Serial No. 318,617.

My invention relates to a new and improved live-wire detector.

@ne or" the objects of my invention is to provide simple, eilicient and portable apparatus for use in power houses or the like,

Whereb the attendant can readily determine W iether a bus bar or other detector is carrying an electric current.

Another object of. my invention is to pr0- Re vide a device of this type which embodies a glow tube, such as a neon tube or the like, of improved form.

Another object of my invention is to provide a device of this type, in which the glow of the neon tube or similar glow tube device is readily visible.

Other objects of my invention will be set forth in the following description and drawing which illustrate a preferred embodi- W ment thereof, it being understood that the above general statement of the objects of my invention is intended to merely generally explain the same, and not to limit it in any manner.

Fig. 1 is a side elevation showing the improved device.

Fig. 2 is a sectional view along the line 22 of Fig. 1.

Fig. 3 is a detail view'showing the glow to lamp and the mount therefor.

Fig. 4 is a sectional view on the line 44 of Fig 2.

Fig. 5 is a detail view showing the front contact of the device.

Fig. 6 is a sectional view on the line 6-6 of Fig. 2.

It has heretofore been proposed to detect the presence of an electric current in a conductor, by using a glow tube, such as a neon tube or the like. However, such devices have hitherto not been so constructed as to make the glow of the tube readil Visible, especially when the tube was held a considerable distance from the attendant.

According to my invention the glow tube N is connected to a planar base member 20, -made of any suitable insulating material, by means of spring sockets and 22. The spring socket 15, which releasably holds the 50 adjacent metal contact end 14 of theglow tube N, is connected to the base member 20 by means of a suitable fastening device 24. This socket 15 is made of any suitable springy metal.

The second socket 22 comprises a plurality of spring arms mounted upon a base which is connected by means of a suitable bolt and nut to a lateral base element 21, which is made of any suitable insulating material, and which is connected to the longitudinal base element 20 by means of a screw or other suitable fastening means.

As shown in Figs. 2 and 3 a condenser C is connected to the spring socket 252. This condenser C may consist of a sheet of copper or other suitable metal bent into cylindrical form, and having its ends separated. This condenser has the effect of increasing the capacity of the adjacent metal contact end of the glow tube N. The glow tube N has a laterally bent portion 11 by means of which the glow of the tube can be readily observed.

The upper end of the longitudinal base member 20 is connected to the reduced end 1a of a support member 1. As shown in Fig. 6 for example, the upper part of the supporting member 1 is semi-cylindrical. As shown in Fig. 4 the reduced upper end 10: of the supporting member 1 has a width which is only slightly greater than the width of the longitudinal base member 20. Thesupporting member 1 is also made of any suitable insulating material.

The supporting member 1 fits within a tube 4', also made of suitable insulating material which is one side thereo rovided with an opening at A hood 4 is provided with a cylindrical surface which is connected to the tube 4. by means of fastening members 26. This hood 4. has a flared portion within which the lat: erally projecting portion 11 of the glow tube.

terial and it is provided with a perforation through which the contact rod 5 extends. This contact rod 5 has a curved-tip 8, which can be caused to contact with the us bar B,

be connected.

other metal end of the tube.

or any other conductor which is to be tested.

The cap 7 is provided with recesses S and S so that it can only be placed within the tube 4' in predetermined position. Likewise, the recesses S and S prevent the cap,

'7 from turning, by cooperating with members 20 and 1a.

A contact spring 6 is connected to the contact rod 5 by means of a nut 9, and a second nut 10 is used for holding the contact rod 5 to the cap 7.

When the parts are assembled the contact 6 touches the adjacent metalcontact end 14 of the glow tube N.

The tube 1 is provided with a threaded extension 2, to which an extension stick 3 can The operation of the device is as follows When the parts are assembled as previously described, a bus bar or the like is tested by applying the tip 8 of the contact rod 5 thereto. If an alternating current is passing through-the said bus bar 13, then the voltage of that portion of said bus bar B which is in contact with the tip 8 changes rapidly. An alternating voltage is therefore impressed upon the tube end 14, which'touches the contact spring 6. The alternating voltage of said metal end 14 inducesa corresponding alternating voltage of opposite sign upon the ends of the tube act like a condenser. Hence, if the upper metal end is given a positive charge, this induces a negative charge'on the adjacent face of the opposite metal end, so that a discharge tends to pass through the adjacent surfaces of the metal ends. If the impressed voltage is sufiiciently high a discharge current passes between the members 14, producing the familiar glow. This is facilitated by the fact that an ungrounded condenserC is employed, merely to increase the capacity of the adjacent end 14:. x

The hood4 which is also made of suitable insulating material keeps light away from the lateral extension 11 of the glow tube, so

that when this glows, it is readily visible.

I have shown a preferred embodiment of my invention, but it is'clear that numerous changes and omissions could be made without departing from its spirit.

I claim: r 1. A live-wire detector comprising a first tubular member made of insulating material having a cut-away and non-tubular extension, a second tubular member made'of insulating material and having a cut-away and nontubular extension connected to said first tubular member, to form a tubular casing having an opening at one side thereof, a hood fitting over said ('Qn(l tubular member and connected thereto, said hood extending over the opening in said casing and being op n at one end thereof, a supporting strip located within'said first tubular member and carrying spaced supporting'means ada ted to engage and support the ends of a ow tube, and contact means connected to saidtubularcasing and. adapted to contact with one of the ends of the glow tube.

2. A device according to claim 1 in which "a condenser is connected to the su porting means which are spaced from sai contact means.

3.v An electrical test stick for detecting the presence of alternating current potentials comprising a housing, an exterior electrical terminal on said housingand adapted to be held at a point of alternating current potential, a neon tube having a luminous portion arranged angularly within said housing and.

The two metal 

